1. Field of the Invention.
This invention relates to self-locking nuts.
2. Description of the Prior Art.
It is a requirement, in many engineering applications, to be able to lock nuts in any position to which they are adjusted without the locking device causing any disturbance of the nut position; in connection, for example, with adjustable ball and taper roller bearings, it is of the utmost importance (when an adjustment has been made in order to give correct running conditions) that the subsequent locking of the parts in position shall not disturb the adjustment. A practised method of doing this is to use a self-locking nut with a nylon or fibre annular insert permanently (namely, not removably) incorporated at that bearing face of the nut which does not carry any load; during the screwing-on or application of the nut, said insert offers to the feed a resistance which causes an upward stress which loads the thread flanks of the nut, shaft or spindle, and metal-to-metal locking takes place.
A disadvantage of this locking method or arrangement is that, after each removal of the nut, the annular insert offers less resistance to the feed than was offered on the previous occasion and, as a consequence, the prevailing torque of the self-locking nut is considerably reduced after each removal; this has the result, of course, of making the assembly less secure and of making the selflocking nut unfit to perform its function.
The principal object of the present invention is to provide a self-locking nut which is free from the above-mentioned operation disadvantage.
Another object of the present invention is to provide a self-locking nut which, in use, will not only provide the required degree of metal-to-metal locking when first used but will also provide that required degree of metal-to-metal locking during a number of subsequent uses of the locking nut.
Yet another object of the present invention is to provide a self-locking nut which can be used on an indefinite number of occasions, with optimum metal-to-metal locking, by means of the supply of replaceable inserts each of which is intended to be used a number of times.